Pushbutton electric switch operator with maintaining mechanism



Sept. 24, 1968 R, A, MUKA; ET Al. 3,402,620

PUSHBUTTON ELECTRIC SW1-TCH OPERATOR WITH MAINTAINING MECHANISM Filed Feb. 4, 1966 2 Sheets-Sheet 1 f5 1 t- 5' .Ago

v r* e sept. 24, 196s R, A. MUKA, ET AL 3,402,620

PUSHBUTTON ELECTRIC SWITCH OPERATOR WITH MAINTAINING MECHANISM Filed Feb. 4, 1966 2 Sheets-Sheet 2 United States Patent O 3,402,620 PUSHBUTTON ELECTRIC SWITCH OPERATOR WITH MAINTAINING MECHANISM Roy A. Mukai, Milwaukee, Allan P. Charbonneau, Wauwatosa, Joseph F. Waldorf, New Berlin, and Robert Pearson, Milwaukee, Wis., assignors to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Filed Feb. 4, 1966, Ser. No. 525,162 9 Claims. (Cl. 74-483) ABSTRACT F THE DISCLOSURE A two-button, one-hole mounting assembly having switch units attached to the rear thereof for reciprocable actuation by one of the buttons. Depression of the actuating button extends a foldable over-center linkage which is biased to travel beyond the center position to abut against a stop to lock the linkage in the extended position and maintain the actuator button depressed. Depression of the second button cams the linkage back to the other side of the center position to allow the linkage to collapse and the actuator button to return.

This invention relates to operating mechanisms for pushbutton type electric switches and more particularly to switches of the oil-tight variety with separable contact blocks and operator assemblies.

An object of this invention is to provide in a compact pushbutton operator a strong and highly reliable mechanism for maintaining a pushbutton mechanism depressed.

It is another object of this invention to provide means for releasing the aforedescribed maintaining mechanism to allow the pushbutton mechanism to return to its original position.

It is still another object of this invention to provide a compact pushbutton operating mechanism in a unitary operator assembly having two pushbuttons effective to move a switching mechanism to opposite positions and having improved means for maintaining the mechanism in one of these positions.

Other objects and advantages of this invention will be evident to those skilled in the art upon reference to the following description and claims.

While the device hereinafter described is adapted to fulll the objects stated it is to be understood that it is not intended that the invention be confined to the particular preferred embodiment disclosed since it is susceptible of various modifications without departing from the scope of the appended claims.

In the accompanying drawings:

FIGURE 1 is a front elevation view of a pushbutton adaptor for an electrical switch assembly embodying the invention;

FIG. 2 is a sectional view of the adaptor shown in FIG. 1 taken on line 2 2 of FIG, l;

FIG. 3 is a partially sectional view of the entire switch assembly and illustrates a sectional view of the adaptor of FIG. 1 taken on line 3 3 of FIG. l;

FIG. 4 is a rear elevation view of the adaptor of FIG. l;

FIG. 5 is a sectional view taken on line 2 2 of FIG. l and is similar to FIG. 2 except that the operating mechanism is shown in another position;

FIG. 6 is a sectional view taken on line 3 3 of FIG. l and is similar to FIG. 3 except that the operating mechanism is shown in the position corresponding to that of FIG. 5 and FIG 7 is an exploded isometric view of parts of the operating mechanism.

3,402,620 Patented sept. 24, 196s ice Referring to the drawings, there is shown a unitary pushbutton assembly comprising two rectangular manually operable pushbuttons 2 and 3 mounted in a frame or retainer 4. The retainer has two front facing recesses 5 and 6 formed in the front surface thereof and divided by a wall 7. Wall 7 is fastened to retainer 4 by riveting a pair of tabs 7a which extend perpendicular from the lower ends of wall 7. Recesses 5 and 6 loosely and slidingly accommodate pushbuttons 2 and 3, respectively, and are of the depth suflicient to allow the pushbuttons 2 and 3 to be depressed to actuate the mechanism. At the rear of the rectangular front portion of retainer 4 there is an integral cylindrical bushing 8 adapted to be inserted through a mounting hole in a panel or the like. The exterior of bushing 8 is threaded to accommodate a nut (not shown) by which the retainer 4 may be securely fastened to the panel. A pair of contact blocks 9 and 10 are fastened side-by-side to the end of bushing 8 by means of a mounting device 11. Contact blocks 9 and 10 are fastened to the device 11 by means of screws 12. The device 11 includes a rotatable latch ring 16 with a pair of lugs (not shown) which engage a pair of grooves 13 formed near the rear of bushing 8. Each contact block 10 is of a well known type having a pushrod 14 which may be reciprocally actuated to operate electrical contacts 15. A compression Spring 17 provides return force to plunger 14. The structure of such contact blocks, the structure of mounting device 11 and the method of mounting the pushbutton assembly are more completely described in the copending application, Ser. No, 520,444, filed Jan. 13, 1966, by Roy A. Mukai, Allan P. Charbonneau, Joseph F. Waldorf and Robert Pearson, now United States Patent No. 3,322,926, and assigned to the present assignee.

Pushbutton 2 is fastened to a plate 19 by means of two lugs 20 (FIG. 2) which snap over the opposite ends of plate 19. A pushrod 21 is riveted to the center of plate 19 and extends downwardly and slidingly through an aperture 22 in retainer 4. A seal 23 made of rubber or similar material encircles the pushrod 21 to prevent the passage of liquids through aperture 22. A washer 24 covers seal 23. A compression spring 25 is interposed between washer 24 and plate 19 to provide a return force to pushbutton 2 Similarly, pushbutton 3 is snap fastened to a plate 26 by two lugs (not shown). A shorter pushrod 27 is riveted to the center of plate 26 and extends downwardly through a loosely fitting aperture 28 in retainer 4. A seal 29 encircles pushrod 27 to seal aperture 28. A washer 30 covers seal 29 and supports one end of a compression spring 31. The other end of spring 31 bears against the lower face of plate 26 to provide a return force to pushbutton 3.

During operation, pushbuttons 2 and 3 are interlocked by a rocker lever 32 which is pivotally supported at its center on retainer 4 by a pin 33. Lever 32 extends through a slot 34 formed in retainer 4 to cooperate at its ends with the mechanisms associated with the pushbuttons 2 and 3. Hooklike brackets 35 and 36 are welded to the lower surfaces of plates 26 and 19, respectively. Pins 37 and 38 are riveted to the opposite ends of lever 32 to loosely engage the hooks of brackets 35 and 36, respectively. Pushbuttons are thereby interlocked so that when pushbutton 2 is depressed, pushbutton 3 must rise and v1ce versa.

An annular shoulder 39 is formed near the lower end of the longer pushrod 22. Immediately below `shoulder 39, pushrod 22 passes through an aperture in a support plate 40 and is there fastened to support plate 40. Support plate 40 is generally circular in shape with a circumferential ridge 41. Plate 40 has two oppositely positioned flattened edges with upstanding flat edges 42. Plate 40 3 looselyand slidingly itswithin a rear recess 43 of retainer 4 and at edges 42 cooperate with attened surfaces 44 formed on the generally cylindrical surface of recess 43. The front surfaces of edges 42 also serve to stop the return motion of support plate lby the engagement of edge 42 against the retainer 4.

Support plate 40 has a center circular aperture 45 and an adjacent smaller circular aperture 46. A rectangular aperture 47 is also formed on plate 40. A U-shaped bracket 48 spans aperture 47 on the lower side of plate 40 and is welded at its ends to plate 40 at opposite edges of aperture 47. A shoulder pin 49 is riveted to the depending bight of bracket 48. Pin 49 and the lower end of pushrod 21 serve to simultaneously push on the pushrods 14 of the contact blocks 9 and 10, when pushbutton 2 is depressed.

In order that pushbutton 2 may be maintained in its depressed postion to thereby maintain the contact blocks 9 and 10 actuated, an over-center linkage mechanism is provide-d between plate 40 and retainer 4. This linkage consists of two pivotally connected links, an upper link 50 and a lower link 51. This linkage is shown in its folded or collapsed position in FIGS. 2 and 3 and is in its locked extended position in FIGS. 5 and 6. Upper link 50= cornprises two similar parallel side portions 52 and 53 rigidly connected by an integral strip 54.

Link 50 is p-ivotally fastened to retainer 4 by a pin 55 which fits loosely through a pair of alined apertures in sides 52 and 53. A cylindrical spacer 56 tits over pin 55 and `between sides 52 and 53. The ends of pin 55 are held within a pair of opposed slots 57 and 58 Within retainer 4. The material of retainer 4 adjacent the edges of slots 57 and 58 is peened over to securely retain pin 55. Another pair of alined apertures are formed in sides 52 and 53 to tightly accommodate a spring holder pin 59.

Link 51 comprises a pair of similar opposite sides 60 and 61 rigidly joined by an integral strip 62. Link 51 is pivotally -connected to link 50 by means of rivets 63 and 64 which pass through a pair of apertures 65 and 66 of link 50 and a corresponding pair of apertures 67 and 68 in link 51. Apertures 65 and 66 fit loosely over the shoulders 63a and 64a, respectively, on rivets 63 and 64. The smaller ends of rivets 63 and 64 are riveted over to securely engage the inner faces of sides and 61. A trip member 69 having three portions 69a, 69b and 69C is welded to side 60. Portion 69a is `welded to side '60; Portion 69b extends perpendicular to portion 69a and away from side 60. Portion 69C is also in a plane perpendicular to side 60 and is bent from portion 69b to form a roughly V-shaped member extending from the side 60 of link 51.

A support channel assembly comprising a channel 70 and a post 71 riveted thereto is pivotally fastened to link 51 by means of a rivet 72 which passes through the apertures 73 and 74 in channel 70 and apertures 75 and 76 in link 51, when alined. Another pair of apertures 77 and 78 are formed in channel 70 to accommodate another spring holder pin 79. A tension spring 80 extends between pins 59 and 79. Post 71 passes through aperture 45 in plate 40 and is therein secured by a spring ring 81 which engages a circumferential groove in post 71. A small nib 82 is formed on the lower surface to index with aperture 46 n plate 40 and thereby prevents undesired rotation of channel 79.

It can be seen that as pushbutton 2 is depressed against the force of spring 26 and the return force of the contact blocks 9 and 10, the linkage of links 50 and 51 is extended against the force of spring 80. When the linkage reaches the center position in ywhich pin 55, rivets 63 and 64 and rivet 72 are aligned, the tension of spring 80' causes rivets 63 and 64 to move over-center until the edge of link 50 abuts the corner 83 of retainer 4 as sho'wn in FIG. 5. The compressive force tending to force rivet 72 toward pin 55 is then ineffective to cause return movement of the mechanism. As a result plate 40 is locked in its depressed position and the contact blocks 9 and 10 are maintained in an actuated position.

In order that the mechanism may return to its original unactuated position, the linkage comprising links 50 and 51 must be unlocked. To this end, a cam member 84 is firmly affixed to the lower end of the shorter pushrod 27. Cam 84 is of sheet metal construction and extends away from pushrod 27 toward link 51 to cooperate with trip member 69 when the link 51 is in its extended position. At the edge of cam 84 which faces the intersections of portions 69h and 69o, a tab 84a is -bent upwardly. It can be seen that when pushbutton 3 is depressed from the position of FIG. 6, through that movement allowed by the looseness in the connections of interlock lever 32, cam 84 strikes portion 69h of trip member 69 to force links 50 and 51 over-center. Thus released, the mechanism is free to return to its original unactuated position under the influence of interlock lever 32, return spring 25 and the return force of contact `blocks 9 and 10. In this connection it is to be noted that spring 25 is made to have a considerably greater return force than spring 31 of the opposite pushbutton 3. Rectangular aperture 47 and bracket 48 are lformed to accommodate the downward movement of pushrod 27 and cam 84.

It can be seen from the foregoing description that the depression of pushbutton 3 actuates contact blocks 9 and 10 and the linkage of links 50 and 51 maintains pushbutton 3 depressed. Depression of pushbutton 3 releases the mechanism to return to its unactuated position. The over-center linkage 0f links 50 and 51 provides an extremely strong maintaining latch which enables the mechanism to reliably withstand the return forces of a great number of stacked contact blocks such as contact blocks 9 and 10, or similar devices. The relatively lo-w friction in the over-center linkage mechanism enables the latch to be easily and reliably tripped or released under relatively high loading.

We claim:

1. A manually operable mechanism for causing actuation of reciprocally actuable electrical switch units comprising:

a supporting frame;

a manually operable reciprocatory means supported :by

said frame having a first position and a second position for -actuating at least one reciprocally actuable electrical switch unit when moved t-o its second positlon;

means Afor biasing said reciprocatory means to its rst position;

latching means comprising an over-center linkage between said frame and said reciprocatory means having two pivotally connected links, one of said links pivotally attached to said frame and the other of said links pivotally connected to said reciprocatory means, said linkage having a center position in which all of lts pivot points are in line;

means for limiting movement of said linkage to one side of its center position to assume a locked extended position in which said linkage is locked against compressive force to thereby hold said reciprocatory means in its second position, said linkage further havling a collapsed position on the other side of said center position in which said linkage folds to permit movement of said reciprocatory means to its first position;

and manually operable trip means for moving said linkage from its locked extended position past its center position to allow said linkage to fold and allow said reciprocatory means to move to its first position.

2. The invention as defined in claim 1 in which Said trip means comprises a second reciprocatory means *supported yby said frame.

3. The invention as defined in claim 2 in which said second reciprocatory means comprises cam means for forcing said linkage from its locked extended position past its center position.

4. The invention as defined in claim 1 together with spring means acting on Isaid linkage to bias said linkage from said center position to said locked extended position.

5. The invention as defined in claim 2 in which each of said reciprocatory means comprises manually operable push-button means.

6. The invention as defined in claim 5 in which Said frame is adapted to be mounted within a single hole in a supporting panel with said pushbuttonzmeans accessible from one side of said panel and with at least one reciprocally actuable switch unit attached to and supported by said frame on the other side of said panel.

7. The invention as defined in claim 2, together with interlocking means =for interlocking the'operation of said first mentioned reciprocatory means and said second reciprocatory means whereby said trip means is forced to a reset position when said first mentioned reciprocatory means is moved to its second position, and wherein said trip means is subsequently operable from said reset position to move said linkage.

8. A pushbutton operated switch assembly of the onehole mounting yvariety comprising:

a frame adapted to be mounted within a single hole in a support panel Iand having a front side and a rear side;

at least one -reciprocally actuable switch unit attached to the rear side of said frame;

first reciprocatory means supported by said frame having a released position and a depressed position comprising manually operable pushbutton means operable from the front side of said frame, said first reciprocatory means communicating at the rear side of said 'frame with said switch unit to cause actuation of said switch unit when moved to its depressed position;

means for biasing said first reciprocatory means to its released position;

latching means comprising an over-center linkage between said frame and saidy first reciprocatory means having two pivotally connected links, one of said links pivotally attach-ed to said frame and the other link pivotally connected to said first reciprocatory means, said linkage having a center position in which all of its pivot points are in line;

means for limiting movement of said linkage to one side of its center position to assume a locked extended position in which said linkage is locked against compressive force to thereby hold said reciprocatory means in its second position, said linkage further having a collapsed position on the other side of said center positionA `in which said linkage folds to permit movement of said first reciprocatory means to its first position;

second reciprocatory means supported by said Iframe comprising manually operable push'button means operable from the front side -of said frame;

trip means connected to said second reciprocatory means for moving said linkage from its locked extended position past its center position to allow said linkage to fold and allow said first reciprocatory means to move to its first position.

9. The invention as defined in claim 8 in which said second reciprocatory me-ans has a released position and a depressed position and said trip means moves said linkage from its locked extended position when said sec-ond reciprocatory means is moved to its depressed position, together with;

interlocking means 4for interlocking the movements of said first and second reciprocatory means so that when said first reciprocatory means is moved to its depressed position, said second reciprocatory means is -forced to its released position and vice versa.

References Cited UNITED STATES PATENTS 1,424,402 8/ 1922 Hartman 200-5 2,369,362 2/ 1945 Marziani 74-520 2,255,905 9/1941 Somers et al 74-483 3,182,160 5/1965 Zavertnik et al 200*l72 3,201,557 8/1965 Poulton 200--172 FRED C. MATTERN, I R., Primary Examiner. W. S. RATLIFF, Assistant Examiner. 

